Jack's "reason", if you can call it that, was hella flimsy. I mean where he and Sawyer are having a talk and Jack implies he's doing what he's doing because of Kate and Sawyer's all "WTF? She's RIGHT there, doc." It would've made more sense if Kate had died in an earlier episode (as she should've!) and then Jack has a motive to want to reset everything. As is stands, he just looks batshit. I only say that because his life wasn't so great to begin with. The writers gave him such a lousy-ass life, it just seems he's better off on the crazy ass island at present where he can get some tail and avoid malpractice suits.
The Jacob stuff was eye-rolling for me, but I did like the Bruce Willis reveal at the end with Locke being a dead guy in a box. The odd thing with Jacob and that other guy at the beginning made me groan like "Fuck, ANOTHER plot line to follow?" Jacob being present for everything reminded of me of those Nikki/Paolo insertion scenes. Ick.
I have the feeling I'm gonna die before I get to see the end. Even if I don't, someone else will and that still kinda blows. If I kick the bucket, someone here better ouija me the ending.